I have a mongoose otero elite 2008 and the crankset is broke (wobbling) It's also bent, so time for a new one. I currently have a nice shimano deore crankset from an old bike, but it uses a different kind of bottom bracket (holllowtech) where as on my bike I have an octalink BB. Can I remove the octalink and buy a hollowtech BB to fit the deore crankset?

You really only have 3 variables -- the width of the BB shell, it's diameter, and the threading.

To my knowledge the diameter is pretty much standard these days (though no doubt some fancy-smancy bike are outside the box), and there are only a couple of standard widths. And last I heard (which was about 10 years ago) only some Italian brands persisted in using oddball threading.